Yamaha XSR 900 2022 Service Manual page 95

2. Remove:
• Rider seat
• Side cover
Refer to "GENERAL CHASSIS (1)" on
page 4-1.
• Fuel tank cover
Refer to "GENERAL CHASSIS (4)" on
page 4-10.
• Fuel tank
Refer to "FUEL TANK" on page 7-1.
• Air filter case
Refer to "GENERAL CHASSIS (5)" on
page 4-11.
3. Remove:
• Service hose cap "1"
1
4. Install:
• Vacuum gauge "1"
Vacuum gauge
90890-03094
Vacuummate
YU-44456
5. Install:
• Air filter case
Refer to "GENERAL CHASSIS (5)" on
page 4-11.
• Fuel tank
Refer to "FUEL TANK" on page 7-1.
6. Check:
• Throttle body synchronization
PERIODIC MAINTENANCE
a. Start the engine, warm it up for several min-
utes, and then let it run at the specified en-
gine idling speed.
Engine idling speed
b. Check the vacuum pressure.
Difference in vacuum pressure
between the cylinders
If out of specification → Adjust the throttle
body synchronization.
Adjusting the throttle body synchronization
1
1. Adjust:
• Throttle body synchronization
a. Start the engine, warm it up for several min-
utes, and then let it run at the specified en-
gine idling speed.
Engine idling speed
b. Using the throttle body that has the bypass
air screw "1" with a white paint mark as the
standard, adjust the other throttle bodies by
turning its bypass air screw in or out.
ECA21300
NOTICE
Do not turn the bypass air screw (white paint
mark) of the throttle body that is the stan-
dard. Otherwise, the engine may run roughly
at idle and the throttle bodies may not oper-
1
ate properly.
TIP
• Turn the bypass air screw using the carburetor
angle driver.
• After each step, rev the engine two or three
times, each time for less than a second, and
check the synchronization again.
• If a bypass air screw was removed, turn the
screw in fully and be sure to synchronize the
throttle bodies.
• If the throttle body synchronization can not be
adjusted using the bypass air screw, clean or
replace the throttle bodies.
• The difference in vacuum pressure between
the throttle bodies should not exceed 1.3 kPa
(10 mmHg).
3-9
1200–1400 r/min
0–1.3 kPa (10 mmHg, 0.4 inHg)
1200–1400 r/min